JPH06156221A - Braking energy regeneration device - Google Patents

Abstract

PURPOSE:To provide a braking energy regeneration device which can prevent the torque loss of a vehicle, and cool a heated part in a hydraulic pump-motor completely. CONSTITUTION:Hydraulic oil used to lubricate and cool a sliding part in the housing of a hydraulic pump-motor 16 is collected in a drain tank 20 through a pipeline P4, and a hydraulic oil circulating means which circulates it as lubricating cooling oil in the housing through a switching control valve 30 is provided with a motor-driven hydraulic pump which is driven intermittently.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention, when braking, drives a pump by a drive shaft of a vehicle to store hydraulic energy, while
The present invention relates to a braking energy regeneration device that can be used as a driving force for a vehicle by driving a motor with hydraulic energy when starting or accelerating.

[0002]

Brake energy regenerative devices have been developed for large vehicles, especially for route buses. Generally, in the operation of a route bus, starting and braking are frequently repeated because the distance between the bus stops is short, and the friction heat generated on the brake drum etc. is generated every time the bus stops, that is, each time when braking. That is, the kinetic energy of the vehicle that is released into the atmosphere as heat energy also increases. Therefore, it was developed to store the energy released during the braking as other reusable hydraulic energy, and to reduce the stored hydraulic energy to the driving force of the vehicle when starting or accelerating. It is a braking energy regeneration device.

This braking energy regenerative device is mainly composed of an accumulator, a hydraulic oil tank, a hydraulic pump / motor and respective operating valves. The accumulator is connected to the hydraulic oil tank via the hydraulic pump / motor. The pump / motor shaft of the hydraulic pump / motor is connected to the drive shaft of the vehicle via a gearbox with a clutch.

According to this device, during braking, the drive shaft of the vehicle causes the hydraulic pump / motor to act as a pump.
The hydraulic oil supplied from the hydraulic oil tank to the hydraulic pump / motor through the hydraulic fluid line is pressure-fed to the accumulator by the hydraulic pump / motor, and the pressure is accumulated as the compression energy of the nitrogen gas sealed in the accumulator. On the other hand, at the time of starting and accelerating, the hydraulic oil accumulated in the accumulator is discharged to the hydraulic oil tank through the hydraulic pump / motor and the pressure fluid conduit, thereby causing the hydraulic pump / motor to act as a motor and to drive the vehicle Assists the driving force.

In the hydraulic pump / motor of this regenerative device,
A swash plate type axial plunger type pump / motor is used. This type of hydraulic pump / motor has a built-in swash plate. By changing the tilt angle of the swash plate, you can switch the mode to pump or motor mode, and also change the discharge amount of the pump. It is also possible to change the magnitude of the torque of the motor.

[0006]

In the above braking energy regenerating apparatus, when the hydraulic pump / motor is not operating as a pump or a motor, the hydraulic pump / motor has a swash plate whose inclination angle is zero, that is, Since the hydraulic oil is rotated in a state in which the discharge amount of the hydraulic oil is zero, the flow of the hydraulic oil does not occur, which causes a problem that the sliding portion (rotating portion) of the hydraulic pump / motor generates heat.

In order to avoid such a problem, the hydraulic fluid is circulated in the housing of the hydraulic pump / motor by the gear pump driven by the pump / motor shaft of the hydraulic pump / motor to prevent such heat generation. However, the drive of the gear pump has a problem that the drive shaft of the vehicle is adversely affected by the torque loss through the pump / motor shaft, and the fuel consumption of the vehicle is reduced. Therefore, it is conceivable to disengage the clutch of the gearbox to disengage the pump / motor shaft from the drive shaft of the vehicle so that the pump / motor shaft of the hydraulic pump / motor is not driven. However, in this case
For example, the process of connecting the clutch of the gearbox and restarting the operation of the hydraulic pump / motor after the brake is pressed during braking until the operation of the hydraulic pump / motor is started. Therefore, there is a problem that a response delay occurs in the operation of the regenerative device, that is, the start of the operation of the auxiliary brake, and a shock occurs when the clutch is engaged, which is not preferable.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a braking energy regenerative device capable of preventing a torque loss of a vehicle and reliably cooling a sliding portion in a hydraulic pump / motor. It is in.

[0009]

In order to achieve the above object, the present invention works as a pump by a drive shaft of a vehicle at the time of braking and sends a pressure liquid from a hydraulic fluid tank to a hydraulic accumulator through a hydraulic fluid line. On the other hand, when starting and accelerating, the hydraulic fluid accumulated in the hydraulic accumulator is discharged to the hydraulic fluid tank through the hydraulic fluid conduit to act as a motor, which assists the driving force of the vehicle drive shaft. The hydraulic fluid used to lubricate and cool the sliding parts in the housing of the pressure pump / motor and hydraulic pump / motor is collected in the hydraulic fluid tank side, and the hydraulic fluid is stored in the housing from the hydraulic fluid tank side. In a braking energy regenerative device including a working fluid circulating unit that circulates as a lubricating cooling liquid, the working fluid circulating unit includes an electrically driven hydraulic pump that is intermittently driven. That.

[0010]

According to the braking energy regenerating apparatus of the present invention, the hydraulic fluid lubrication means provided with the electric hydraulic pump driven intermittently lubricates the sliding portion in the housing of the hydraulic pump / motor. And the working fluid used for cooling is collected on the side of the working fluid tank, and the working fluid is circulated from the side of this working fluid tank in the housing as a lubricating cooling fluid.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the accompanying drawings. The braking energy regeneration device is mainly
Piston type accumulator device, hydraulic pump / motor 16, hydraulic oil tank 17, clutch gearbox 18
And a control unit 25.

The accumulator device is an accumulator 1
0, and these accumulators 10 are hydraulic cylinders having two pressure chambers 12 and 13 via a piston 11. These accumulators 10 are
One pressure chamber 12 is filled with a predetermined pressure of nitrogen gas, and the other pressure chamber 13 is capable of accumulating hydraulic pressure. The pressure chamber 13 is connected to the first port 16a of the hydraulic pump / motor 16 via the switching valve 15 and the conduit P1.
The second port 16b of the hydraulic pump / motor 16 has a conduit P
It is connected to the hydraulic oil tank 17 via 2. The hydraulic oil tank 17 is composed of a tank having a predetermined capacity, and a predetermined amount of hydraulic oil is stored in this tank. This hydraulic oil is used not only for delivering energy but also as cooling oil.

Reference numeral 10a in FIG. 1 denotes a bottom cap, and the bottom cap 10 of one accumulator 10 is shown.
A stroke sensor (not shown) is provided in a. This stroke sensor is used in the control unit 2
When the piston 11 in the accumulator 10 moves to the bottom cap 11a side, it is detected that the piston 11 hits, and this detection signal is supplied to the control unit 25.

The switching valve 15 is a control unit 25.
Is normally electrically connected to the hydraulic pump / motor 16, and is normally in the first switching position that allows only the flow of hydraulic oil from the hydraulic pump / motor 16 to the accumulator 10. When accelerating, it is switched to the second switching position that allows the flow of hydraulic oil from the accumulator 10 to the hydraulic pump / motor 16.

The hydraulic pump / motor 16 is composed of a swash plate type axial plunger type pump, and its rotation direction is always fixed. The hydraulic pump / motor 16 is controlled by the control unit 25 via an electric hydraulic pump (not shown) provided with an inclination of its swash plate, and operates as a pump during braking to start and accelerate. Sometimes it works as a motor. Further, the hydraulic pump / motor 16 operates in a neutral state between the pump and the motor when the vehicle is stopped and normally traveling.

Further, the hydraulic pump / motor 16 has a housing, and a drain port 16c and a filling port 16d for hydraulic oil are provided in the housing. A drain tank 20 is connected to the drain port 16c via a conduit P4, and the drain tank 20 has
The switching control valve 30 is connected via the hydraulic pump 21 and the check valve. The hydraulic pump 21 is an electrically driven pump, and is electrically controlled by the control unit 25. Further, the switching control valve 30 is provided with the inlet 1 of the hydraulic pump / motor 16 via the pipe P5, and the pipe P6.
A hydraulic oil tank 17 is connected via.

The switching control valve 30 is composed of an electromagnetic switching valve with two positions in three directions, and is electrically connected to the control unit 25 and controlled. This switching control valve 30
Is normally the hydraulic pump 21 from the drain tank 20 side.
Is set to the first switching position 30a that allows the flow of the hydraulic oil to the hydraulic oil tank 17 side through the like, and when energized, the hydraulic oil is supplied from the drain tank 20 side to the inlet 16d of the hydraulic pump / motor 16 through the hydraulic pump 21 and the like. Is set to the second switching position 30b that allows the above flow.

On the other hand, in the drain tank 21, excess hydraulic oil that has been lubricated inside the hydraulic pump / motor 16 is discharged through the pipe line P4. Incidentally, reference numeral 32 in FIG.
Indicates a level switch, and this level switch 3
No. 2 operates the hydraulic pump 21 via the control unit 25 when the level of the hydraulic oil in the drain tank 20 becomes equal to or higher than a predetermined amount, so that the check valve 31, the switching control valve 30, and the conduit 6 are removed from the drain tank 20. The hydraulic oil tank 17 is replenished with hydraulic oil. In addition, the hydraulic oil tank 17
Even when the hydraulic oil therein falls below the set capacity, the hydraulic oil is similarly replenished from the drain tank 20 side to the hydraulic oil tank 17 side.

The control unit 25 switches the switching control valve 30 to the second switching position 30b at regular intervals,
The hydraulic oil is supplied from the drain tank 20 to the inlet 16 of the hydraulic pump / motor 16 through the hydraulic pump 21, the check valve 31, the switching control valve 30 and the conduit P5. As a result, the hydraulic oil is circulated in the housing of the hydraulic pump / motor 16 at regular intervals, and heat generation in the sliding portion (rotating portion) in the hydraulic pump / motor 16 is prevented.

An air tank 19 is connected to the hydraulic oil tank 17 through a pipe line P3. In practice, an air supply valve (not shown) for controlling the air pressure supply from the air tank 19 to the hydraulic oil tank 17 is provided in the pipeline P3. These valves control the pressurization of air to the hydraulic oil surface in the hydraulic oil tank 17 to enhance the pump suction performance when the hydraulic pump / motor 16 operates as a pump. As a result, it is possible to prevent the occurrence of cavitation at the pump suction port of the hydraulic pump / motor 16.

A relief pipe line (not shown) is connected between the hydraulic oil tank 17 and the switching valve 15.
Actually, when the hydraulic pressure of the hydraulic oil in the accumulator 10 reaches the predetermined pressure by the relief valve provided inside the switching valve 15, the high pressure hydraulic oil is returned from the switching valve 15 to the hydraulic oil tank 17 through the relief pipe line. Be done. Further, as shown in FIG. 1, the hydraulic pump / motor 16 has its pump / motor shaft connectable to a connecting shaft J1 via a gearbox 18 with a clutch, and the connecting shaft J1 is connected to the differential gear 22. Is connected to the axle of the drive wheels of the vehicle. The differential gear 2
2 is connected to an output shaft of a transmission 23 of an engine 24 via a propeller shaft J2.

The clutch of the gearbox 18 is electrically connected to the control unit 25, and when an ON signal is supplied from the control unit 25 and the clutch is turned ON, the pump shaft of the hydraulic pump / motor 16 and its corresponding unit are operated. Connect the gear train, that is, the drive axle of the vehicle,
On the contrary, when the off signal is supplied from the control unit 25 and the clutch is turned off, the pump shaft of the hydraulic pump / motor 16 is disconnected from the drive shaft of the vehicle. The clutch is normally engaged and disengaged when traveling at high speed.

On the other hand, the control unit 25 is composed of a microcomputer and the like, and in addition to the switching valve 15, the clutch of the gearbox 18 and the hydraulic pump for switching the mode of the hydraulic pump / motor 16, the control unit 25 includes: Various sensors are connected. That is, the brake sensor 26 and the accelerator sensor 27 are electrically connected to the control unit 25.

When the brake pedal is operated, the brake sensor 26 supplies the sensor signal to the control unit 25. Further, the accelerator sensor 27 supplies the sensor signal to the control unit 25 when the accelerator pedal is operated. Next, the accumulator 10
Hydraulic pressure is accumulated in the main and sub air tanks 19,
The operation of the above-described braking energy regeneration device will be described on the assumption that the air pressure in 20 is accumulated. When starting and accelerating, the accelerator pedal is operated, and a sensor signal from the accelerator sensor 27 is sent to the control unit 25.
Is supplied to the control unit 25, the control unit 25 determines that the vehicle is starting or accelerating, and switches the switching valve 15 of the accumulator 10 to the second switching position, while switching the hydraulic pump / motor 16 to the motor mode. . At this time, the hydraulic oil accumulated in the accumulator 10 passes through the hydraulic pump / motor 16 and the pipeline P2, and the hydraulic oil tank 1
7, the hydraulic pump / motor 16 generates torque, which is transmitted to the drive axle of the vehicle via the gearbox 18. As a result, the driving force of the vehicle is
The torque of the hydraulic pump / motor 16 helps the vehicle to smoothly start and accelerate.

At this time, the control unit 25 detects that the piston hits the stroke sensor 11a, switches the switching valve 15 to the first switching position, and stops the discharge of hydraulic oil from the accumulator 10. Therefore, the vehicle travels only with the driving force of the engine 24 as in a normal vehicle. At this time, the hydraulic pump / motor 1
6 is driven in a neutral state between the pump and the motor, the angle of the swash plate of which is inclined to zero.

During braking, when the brake pedal is operated and a sensor signal is supplied from the brake sensor 26 to the control unit 25, the control unit 25
When it is judged that braking is in progress, the switching valve 15 of the accumulator 10 is switched to the first switching position, and the hydraulic pump
The motor 16 is switched to the pump mode. At this time, the driving force of the vehicle is transmitted from the drive axle to the pump shaft of the hydraulic pump / motor 16 via the gearbox 18, and the hydraulic pump / motor 16 outputs the hydraulic oil from the hydraulic oil tank 17 through the pipelines P2 and P1. The hydraulic pressure is accumulated by pumping to the accumulator 10. Then, when the hydraulic pressure is accumulated in the accumulator 10 to a predetermined pressure, the high-pressure hydraulic oil is returned to the hydraulic oil tank 17 via the relief pipe line P3.
At this time, the nitrogen gas in the accumulator 10 is compressed,
The driving force of the vehicle, that is, the kinetic energy is accumulated in the accumulator 10 as the static pressure energy of nitrogen gas.
In this way, the accumulated energy stored in the accumulator 10 is used again when starting and accelerating.

According to the braking energy regeneration device described above,
Since the hydraulic oil is driven by the electrically driven hydraulic pump 21, there is no extra pump driven by the hydraulic pump, the pump of the motor and the motor shaft, and the adverse effect of torque loss on the drive shaft of the vehicle can be prevented. The effect of improving the fuel efficiency of the vehicle can be obtained. Further, since torque loss can be prevented, it is not necessary to disengage the clutch of the gear box 18, and there is no response delay in the operation of the regenerative device and no shock due to clutch engagement. Further, the hydraulic oil is supplied to the housing of the hydraulic pump / motor 16 at regular intervals so that the hydraulic oil is circulated.
When the motor 16 is not operating as a pump or a motor, it is possible to reliably cool the sliding portion in the hydraulic pump / motor 16 even if heat is generated.

It is needless to say that the present invention is not limited to the above-mentioned embodiment and can be variously modified. For example, the switching control valve 30 is switched to the second switching position 30b at regular intervals, but it may be switched at constant rotational speeds of the pump / motor shaft of the hydraulic pump / motor 16, or at the hydraulic pump / motor. The switching may be performed when the internal temperature of 16 reaches or exceeds a predetermined temperature.

[0029]

As described above, the braking energy regenerative device of the present invention collects the hydraulic fluid used for lubricating and cooling the sliding portion in the housing of the hydraulic pump / motor to the hydraulic fluid tank side. In the braking energy regenerating device including a hydraulic fluid circulating means for circulating the hydraulic fluid from the hydraulic fluid tank side into the housing as a lubricating cooling fluid, the hydraulic fluid circulating means is an electrically driven type that is driven intermittently. Since it has a hydraulic pump, the hydraulic pump, motor pump,
Since there is no extra pump driven by the motor shaft, the adverse effect of torque loss on the drive shaft of the vehicle can be prevented, and the running fuel efficiency of the vehicle can be improved. Further, since the hydraulic fluid is circulated intermittently in the housing, it is possible to reliably cool even if the sliding portion in the hydraulic pump / motor generates heat.

[Brief description of drawings]

FIG. 1 is a schematic system configuration diagram of a braking energy regeneration device.

[Explanation of symbols]

 10 Accumulator 15 Changeover Valve 16 Hydraulic Pump / Motor 17 Hydraulic Oil Tank 18 Gear Box (with Clutch) 19 Air Tank 20 Drain Tank 21 Hydraulic Pump 25 Control Unit 30 Changeover Control Valve 32 Level Switch P1, P2, P3, P4, P5, P6 Pipeline

Claims (1)

[Claims] 1. During braking, the drive shaft of the vehicle acts as a pump to pump the pressure fluid from the hydraulic fluid tank to the hydraulic accumulator through the pressure fluid conduit to accumulate the pressure fluid, while at the time of starting and accelerating, the hydraulic accumulator is activated. In the housing of the hydraulic pump motor and the hydraulic pump motor that acts as a motor by discharging the accumulated hydraulic fluid to the hydraulic fluid tank through the hydraulic fluid line and assisting the driving force of the vehicle drive shaft. Braking provided with a hydraulic fluid circulating means for collecting the hydraulic fluid used for lubricating and cooling the sliding portion on the hydraulic fluid tank side and circulating the hydraulic fluid from the hydraulic fluid tank side in the housing as lubricating cooling fluid. In the energy regeneration device, the braking energy regeneration device is characterized in that the hydraulic fluid circulating means includes an electrically driven hydraulic pump that is intermittently driven.